#include <iostream>
#include <unistd.h>
#include <pthread.h>

using namespace std;

int tickets = 1000;
pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;

void *threadRun(void *arg){
    const char *name = (char *)arg;
    while(1){
        pthread_mutex_lock(&mutex);
        if(tickets > 0){
            usleep(1000);
            printf("%s get a ticket, left: %d\n", name, --tickets);
            pthread_mutex_unlock(&mutex);
        }
        else{
            pthread_mutex_unlock(&mutex);
            break;
        }
        //后面还有动作,抢完票不代表结束(所以无动作时都只是一个线程)
        //有后续动作时其他线程才有机会抢票
        usleep(1000);
    }
    printf("%s quit\n", name);
    pthread_exit((void*)0);
}

int main(){
    pthread_t t1, t2, t3, t4;
    pthread_create(&t1, NULL, threadRun, (void *)"thread 1");
    pthread_create(&t2, NULL, threadRun, (void *)"thread 2");
    pthread_create(&t3, NULL, threadRun, (void *)"thread 3");
    pthread_create(&t4, NULL, threadRun, (void *)"thread 4");

    pthread_join(t1, NULL);
    pthread_join(t2, NULL);
    pthread_join(t3, NULL);
    pthread_join(t4, NULL);

    return 0;
}